With Bulgaria strengthening its border security measures, migrants crossing the country to Serbia en route to western Europe “face tougher checks from police,” the BBC's Nick Thorpe says in a news report published on Sunday.

The migrants who walk through the mountain passes between Bulgaria and Serbia every night “are afraid of the Bulgarian police, afraid of the cold, but above all afraid that Europe will not accept them after all.”

The author recalls the shooting death of an Afghan migrant in southeastern Bulgaria near the border with Turkey in October in what has been described by the Bulgarian police as an accident – a version questioned by Krassimir Kanev, head of Bulgarian Helsinki Committee human rights group.

Thorpe quotes Bulgaria's Deputy Interior Minister Philip Gounev as telling the BBC that “allegations of police mistreatment are ' 'isolated instances', not a reflection of basic shortcomings.”

"There are cases of corrupt officers. We take these very seriously, and it is a high priority to make sure they are investigated and prosecuted," Gounev has said.a